1. Field of the Invention
The present invention relates to a disc recording and reproducing device, and particularly relates to a disc recording and reproducing device capable of additionally recording, after recording of record data on a disc is once interrupted, record data that is continuous to the record data written just before the interruption.
2. Description of the Related Art
A recordable CD disc, DVD disc or the like before recording is a substrate on which only guide grooves for guiding a laser beam are formed, and an irradiation of a high-power laser beam on the guide grooves causes a reflective transformation in a recording film on the substrate. Record data such as sound data, image data or the like can thus be recorded on a CD disc, a DVD disc or the like, and this recorded record data can be reproduced by a reproducing device.
When recording data on such a recordable disc, for example, a disc recording and reproducing device installed in a personal computer or the like is used. In such a disc recording and reproducing device, record data to be recorded is stored in a buffer once, and this record data stored in the buffer is sequentially recorded at a predetermined rate on the disc.
However, the personal computer or the like performs various processings besides storing record data in the buffer of the disc recording and reproducing device, and it is possible that the buffer becomes empty for some reason and the recording of record data on the disc is interrupted. This phenomenon is generally referred to as “buffer under-run.” When this buffer under-run occurs and the recording is aborted at this point, recording on a CD-R (CD-Recordable) or the like, which is capable of recording only once, is terminated incompletely and the subsequent recording cannot be carried out, so that this CD-R is wasted.
Accordingly, among the disc recording and reproducing devices, there exists a type that detects the end of recorded data on a disc after recording of the record data on the disc is once interrupted, and is capable of resuming writing of record data, which is continuous to the recorded data that is written just before the interruption, at an unrecorded region just after the end of the recorded data. Here, the disc recording and reproducing device of this type is referred to as a disc recording and reproducing device capable of recording interruption and resumption.
In such a disc recording and reproducing device capable of recording interruption and resumption, a displacement may occur between a phase of a reproduction synchronization signal in a recorded data region and a phase of a reproduction synchronization signal in an additional data region. Accordingly, Japanese Patent Application No. 2001-368102 (Japanese Patent Laid-open No. 2003-173535: hereinafter, referred to as patent document 1) discloses a technique for estimating in advance the displacement of the phases of both signals and compensating the displacement when actually resuming recording of record data that is interrupted.
Specifically, as shown in FIG. 1 to FIG. 3, a synchronization signal phase measuring section 32 is provided in the disc recording and reproducing device, and a synchronization signal phase measuring section 32 measures a phase of a reproduction synchronization signal that is a reproduced synchronization signal, so that a connection state between recorded data and additional data is judged from a measurement result of the phase of the reproduction synchronization signal in order to obtain a correction value (error amount) for a correct connection state. Then, a generation timing and a recording resumption timing of record data are controlled so as to compensate the obtained error amount. Measurement of such a correction value (error amount) is, for example, performed using a test writing region of a disc.
However, the technique of the patent document 1 has a problem that, when the reproduction synchronization signal is disturbed (displaced or undetected) due to various external disturbance (in rotation control of a disc by a displacement or flaw of the disc or the like), the disturbed reproduction synchronization signal is used to measure an displacement of the phase, so that the phase difference displaced due to actual recording operation cannot be measured stably.